Last week (p 588) we presented the case of Ruth, a 66 year old housewife who presented to her general practitioner with a two to three month history of feeling “out of sorts” and an erythematous papular rash affecting the fingers, dorsum of the hands, knees, elbows, and neck. We invited responses on the likely diagnosis, further investigation, and what to tell the patient. To look at the rapid responses and discussion of the case so far go to bmj.com (http://www.bmj.com/cgi/content/full/326/7389/588).

Ruth was referred to a consultant dermatologist, who agreed that the most likely diagnosis was dermatomyositis. A skin biopsy showed a sparse lymphocytic inflammatory infiltrate and mild upper dermal oedema. Immunofluorescence gave non-contributory and non-specific results: IgG and C3 tested negative, IgA showed …